Tube rolling on Modwright Sony 5400ES


I would like to replaced the stock 6SN7W tubes with Sylvania JAN-CHS-6SN7W tall bottle. Any difference in the metal base(6SN7 A L 4 stamped on top of tube), and the black base(6SN7 W B 5 stamped on top of tube)?
xavier1

Showing 2 responses by mechans

What really matters is the maker of the tube and then if you know that then you can tell what the date code might be.
I should have added that your choice "Sylvania Jan" is a very good on indeed!